Automatic switch



June 20, 1950 A. c. REID ETAL AUTOMATIC SWITCH 13 mam m Q w? W m m 5 8 i n w h Filed Oct. 20, 1945 Patented June 20, 1950- AUTOMATIC swrron Alexander C. Reid, Genoa, Ill., and Hans P. Boswau, Lorain, Ohio., assignors to Leich Electric Company, Genoa, 111., a corporation of Illinois Application October 20, 1943, Serial No. 506,990

Claims.

The present invention relates to magnetic clutches for use in automatic switches, for example, cross-bar switches such as are employed in establishing connections between subscribers lines in an automatic telephone system.

In a known type of cross-bar switch, described in the U. S. patent to Boswau, No. 2,322,219, granted June 22, 1943, so-called tens and units selector bars are used to control the establishment of connections. In the Boswau switch the selector bars are operated by means of individual electromagnets, one for each selector bar. In a modification of this switch which is disclosed in the patent to Blackhall, No. 2,396,077, granted March 5, 1948, common operating magnets are used to operate the selector bars, there being one operating magnet for the tens selector bars and another operating magnet for the units selector bars. In the Blackhall switch means must be provided for selectively coupling theselector bars to their common operating magnets.

The object of the present invention is the provision of a new and improved selectively controlled coupling arrangement adapted for use in the Blaclrhall switch or in any other situation where similar requirements have to be met. The preferred arrangement comprises a plurality of magnetic clutches, one for each selector bar. Each magnetic clutch comprises a solenoid and two cores, one of which is secured to the associated selector bar. The second core is normally maintained separated from the first core by a spring. When the solenoid is energized, the second core is moved into engagement with the first core, to which it becomes magnetically coupled, this movement of the second core also bringing it into operative relationship with an armature or other actuating member adapted to be operated by the common operating magnet. The preliminary movement of the second core referred to above is made use of to operate a set of-contact springs, one of which is arranged to close the circuit of the common operating magnet. The ensuing energization of the operating magnet moves the second core in a direction opposite to the direction of its preliminary movement, and moves the first core also, due to its being magnetically coupled to the second core. The movement of the first core operates the attached selector bar.

The invention will be described more in detail hereinafter, reference being had to the accompanying drawing, in which- Fig. 1 is a partial front view of the selection control unit of a cross-bar switch embodying the invention;

Fig. 2 shows one of the magnetic clutches, with the solenoid in section;

Fig. 3 illustrates the common actuating member for the tens selector bars in section and its coaction with one of the cores of a magnetic clutch; and

Fig. 4 is a diagrammatic circuit drawing showing the circuit of one of the clutch solenoids and also the circuit of the associated common operating magnet.

The complete cross-bar switching mechanism to which the invention is applied is described fully in the Blackhall patent hereinbefore referred to and consequently it will not be necessary to go into the details of such switching mechanism in the present application. It may be noted, however, that the switching mechanism comprises a plurality of upright trunk units, a test unit, and a selection control unit, all arranged side by side on a base. The upper portion of the selection control unit is shown in Fig. 1. No trunk units are shown, nor is the test unit shown, but it will be understood that these units are arranged to the left of the selection control unit.

Describing the switching mechanism a little more, there are a plurality of sets of line and test bars such as In which are arranged in ten vertical rows and which extend through all the trunk units and the test unit. These bars have terminals such as H at the selection control unit. There may be one hundred sets of bars, giving the switching mechanism a capacity of one hundred lines,

Each trunk unit is individual to a trunk line and is provided with tens and units actuators by means of which the associated trunk line may be connected to any line of the one hundred lines which terminate on the sets of line and test bars. The establishment of such a connection requires the selection and operation of one tens actuator and one units actuator. These actuators, when operated, close electrical contacts which establish the connection.

The actuators are selected by means of selector bars, of which there may be ten tens selector bars for selecting tens actuators and ten units selector bars for selecting units actuators. The ten tens selector bars are arranged parallel to each other in a horizontal plane and extend through the test unit and all the trunk units. Two of these selector bars are indicated at 2| and 22, Fig. 1. The units selector bars are arranged parallel to each other in a vertical plane and also 3 extend through all the trunk units. units selector bar is indicated at 2.

The foregoing will be sumcient to make clear the general arrangement of the cross-bar switching mechanism to which the invention is applied. As indicated hereinbefore, the invention relates to an arrangement for selectively operating the selector bars by means of common tens and units operating magnets. The bars are operated by moving them longitudinally to the right as seen in Fig. 1 against the tension of springs such as 23 which restore the bars when they are uncoupled from the common operating mechanism.

The selection control unit partly shown in Fig. l embodies the common operating mechanism for the selector bars. It includes a vertical rectangular frame l3 having a horizontal top shelf it. On this shelf the solenoids which form parts of the magnetic clutches associated with the tens selector bars are mounted. Two of these solenoids are indicated at El and 32, solenoid i being partly concealed by the frame. There are ten of these solenoids corresponding to ten tens selector bars and they are arranged in two rows, the solenoids of the second row being staggered with reference to those in the first row. The ten units solenoids, of which the upper solenoid it is shown, are mounted in a single vertical row on a web I5 which forms part of the frame.

The tens operating magnet ii is supported between the extension !9 of the frame and a corresponding extension at the rear. The tens operating magnet has an armature 2 carried on the armature yoke 25 which is pivoted at 25c on the two frame extensions such as It. This armature yoke 25 includes an integrally formed horizontal actuating member 28 which spans the rows of tens solenoids. When the operating magnet ll is energized the actuating member 28 moves to the right, operating any tens selector bar that may be coupled to it by the associated magnetic clutch, as will be described in detail hereinafter.

The units operating magnet it is also supported between the frame extensions such as S5 and has an armature 25 which is carried on the pivoted armature yoke 2?, the pivot point being indicated at 2%. The armature yoke 21 has a downwardly extending finger 25 the lower end of which moves to the right when the operating magnet 18 is energized, thereby operating pivo ed auxiliary armature yoke including vertical actuating member 36 which spans the row of units solenoids such as i In the on 'ation of the auxiliary armature yoke the lg member moves to the right, operating any units selector bar that may be coupled thereto by the associated magnetic clutch.

.It will be understood that the of the arrangement of operating magnets a; .1 their associated actuating members is more or less immaterial so long as provision is made for applying a substantially straight line pull to the selector bars. The arrangement which is rather briefly described herein is the arrangement which is dis closed in the patent to Blackhall previously referred to.

The construction of one of the magnetic clutches may now described. For this purpose attention may be directed to etic clutch which includes the solenoid 532 and W1" ii is associated with the eccnd tens selector In this connection it will be understood that solenoid 3!, which is the first solenoid in the first row, is associated with the first tens selector bar 2! solenoid 32. which is the first solenoid in the The upper second row, is associated with the second tens selector bar 22; the remaining solenoids in the first row are associated with the remaining odd numbered tens selector bars; while the remaining solenoids in the second row are associated with the remaining even numbered tens selector bars.

The solenoid 32 comprises a shell 4| of soft iron, Fig. 2, in which there is a spool 32 carrying the winding 43. The ends of the winding are connected to terminals 45 and 45 which are attached to one of the heads of the spool 42. The other spool head has a projection 41 which fits in an opening in the bottom of the shell M. This projection properly locates the spool in the shell and prevents it from rotating therein. The open end of the shell M is closed by an iron washer 44 which has notches in its edge for the terminals 55 and 46. This Washer should have a press fit in the end of the shell. A bracket 48 is secured to the bottom of shell M, by spot welding, for example, and is fastened to the shelf Id of the frame by means of screws such as 49. Thus the solenoid 32 is firmly secured to the shelf.

The complete magnetic clutch which includes the solenoid 32 also includes the two cores 5i] and 5| which are freely slidable in the bore of spool 42. It will be noted in this connection that the openings in the bottom of shell M and washer 44 which are provided for the cores 5E and 5|, respectively, are slightly larger than the bore of the spool, so that the cores are maintained out of contact with the shell and washer. These air gaps in the magnetic circuit should be small, but are desirable to prevent the cores from sticking to the shell or to the washer when the solenoid is energized. The core 50 is secured to the selector bar 22 in any suitable manner. So far as the present invention goes, the two may be more or less permanently connected; but a detachable coupling including the shell 52 may be used if desired. This type of coupling is disclosed in the Black hall patent previously referred to.

Continuing with the description, it will be seen that the core 5| has attached thereto a rod 53, which includes a section 54 of larger diameter and a flanged head 55. These parts are best seen in Fig. 3. Section 54 is located in an open slot 56 in the lower edge of the horizontal actuating member 28 which forms part of the tens operating magnet armature yoke. In order to support the rod in slot 55, also other similar rods in their slots, a slotted plate 51 is provided, having slots such as 58 which are open at the top. The plate 5! may be fastened to the actuating member 23 by countersunk screws, or in any suitable manner.

The left side of the actuating member 28 of the armature yoke bears against a cup washer 59, which is prevented from sliding on section 54 of the rod 53 by means of a split ring 65. Another cup washer 5| bears against the plate 57. A coiled spring 62 is compressed between the washer BI and the flange on the head 55 and normally maintains the parts in the position in which they are shown. The rod 53, or rather the section 54 thereof, is slidable in the slots 55 and 58.

The above description of the magnetic clutch including solenoid 32 and associated parts applies also to the other four magnetic clutches the solenoids of which are located in the same row with solenoid 32. The other five magnetic clutches for the tens selector bars, including the magnetic clutch of which solenoid- 3| forms-a part, are the same also, except that since 1 the solenoids are in a different row and are farther away from the actuating member 28 the rods such as 53 are somewhat longer than the cor.- responding rods such as 53. i The tens operating magnet armature yoke 25 has attached thereto a plate 64 which extends across the armature yoke parallel to the actuating member 28. On the plate 64 there arev mounted ten sets of contact springs which ,are in alignment, respectively, with the ten tens selector bars and with the ten rods such as 53. and 53 which are included in the magnetic clutches. The set of contact springs 65 shown in Fig. 1, for example, is in alignment with the tens selector bar 2| and with the associated rod 53'. The ten sets of contact springs are controlled by the ten rods such as 53 and 53. This may be explained in connection with Fig. 2, which shows the set of contact springs which is associated with the selector bar 22 and rod 53. This set includes the movable or working contact springs 61, 68 and H, the first of which is provided with an operating rod 13. The rod 13 passes through an opening in contact spring 66, is fixed to contact spring 61, and is engaged by an insulating bushing carried by contact spring 68. Contact sprin H has a similar operating rod 73'. The working contact springs 61, 68 and H are tensioned to the left, but are held in the position in which they are shown by the spring 62, which holds the rod 53 to the right as far as it can go, with washer 59 bearing against the side of the actuating member 28. The head 55 of rod 53 is provided with an insert 14 of insulating material, which engages the left hand end of the operating rod 13 and maintains the working contact spring 61 out of engagement with contact spring 66. At the same time the other end of the operating rod I engages the bushing on the working contact spring 68 and maintains.

the spring 68 in engagement with the contact spring 69, while the bushing engages the rod 13' and holds the contact spring II in engagement with contact spring 12.

The mechanics of the operation of the tens selector bar 22 may now be explained, with special attention to the functioning of the magnetic clutch. The selector bar is selected for operation by the energization of the tens solenoid 32, a suitable circuit for energizing the solenoid being provided, as shown in Fig. 4. This circuit will be described shortly.

Upon the energization of solenoid 32 the core 50 attached to selector bar 22 remains stationary, or substantially so, due to the tension in the selector bar restoring spring, which urges the selector bar to the left. The core however, is drawn into the solenoid 32 upon the energization thereof until it engages the core 50, thus closing the magnetic circuit except for the small air gaps at the points where the cores pass through the shell 4| and washer 44. The movement of core 5| and the rod 53 attached thereto, which slides in the slots 56 and 58, compresses the spring 62 and permits the working contact springs 61, 68 and II to shift to their operated positions in which contact spring 61 engages contact spring 66, contact spring 68 separates from contact spring 69, and contact spring 1| separates from contact spring 12 and engages contact spring 10. Spring 62, it may be remarked,

is a somewhat lighter spring than the selector 1;;

6 bar restoring spring and besides this the spring- 62 is opposed by the tension in the working contact springs. .The movement of the core 5| and rod 53 to the. left brings the head 55 of the rod 53. intoengagement or nearly into engagementv with the washer 6| The adjustment of the parts should be'such as to insure the engagement of c0re 5|; with core 50, with as little space as is practicable between the head 55 and washer 8|, The switch'comprising the contact springs 6? and 66 is used to control the tens operating magnet .11 over a suitable circuit and the magnet energizes when the switch is closed. The armature 24 is accordingly attracted, the armature, yoke 25 is rotated on its pivots 25a, and the actu ating member 28 forming part thereof is moved to the right. This, movement of the actuating. member 28 has no effect as regards any of the, tens selector bars except the selector bar 22. The

magnetic clutches associated with the other selec-e tor bars arenot energized and consequently the cores corresponding to core 5| are merely drawn.

to the right, the cores sliding freely in their asso-v ciated' solenoids. But in the case of the selector bar 22, the associated solenoid 32 is'energized.

and .core 5| is magnetically coupled to core 58. When the 'actuatingmember 28 moves to the right, therefore, the selector bar 22 is operated. More in detail, .the washer 6| engages the head 55 of rod moves the rod to the right,

carrying the attached core 5| along with it. Core 55, being now magnetically coupled to core 5|,

is moved also and operates the attached selector bar 22.

tance and their movement does not alter-the value of the flux in the magnetic circuit. 7 It will, be noted also that since the set of contact springs;

66,- 61, etc. is mounted on the'armature yoke the operation just described does not alter the posi-;

tion of the contact springs relative to the head 55 of rod 53.

. When the selector bar 22 has remained opv erated aslong as required, the circuit of solenoid 32 isopened and the magnetic clutch becomes deenergized or released, permitting cores 50 and 5| to separate. The selector bar 22 is accordingly moved to the left by its restoring spring A fixed stop. 36- is provided which arrests the, movement when the selector bar reaches its nor-.

mal position. At the same time the spring 62 moves the rod 53 to the right and thus restores the associated set of contact springs to normal position. The switch 66-61 being thus opened, the tens operating magnet I! is deenergized and the armature yoke and actuating member 28 are restored by gravity to their normal position,

in which a short arm 15 of the yoke engages the and need not be described in detail. The clutch, associated with the selector bar I2, for example, comprises the solenoid l6, the core attached to selector bar l2, and the core 8| having the attached rod 83. When the solenoid I6 is energized, the corev 8| moves to the left into engagement with core Bi) and the rod 83 permits the The movement of the cores 5| and so is unopposed magnetically since bothcores extend outside the solenoid for a substantial dis-;-

associated set of contact springs to shift position. The switch comprising contact springs 84 and 85 thereupon closes a circuit for the common operating magnet 18, which energizes and operates its armature 26 and armature yoke 21, pivoted at 21a, moving the lower end of the finger 29 to the right. The auxiliary armature yoke, pivoted on a vertical axis at the back side of the frame, is rotated on its pivots by the finger 29 and the actuating member 30 is moved to the right. This movement of the actuating member operates the selector bar l2 by means of rod 83, core 8i, and core 80 which is now magnetically coupled to core 8|.

When the solenoid 16 becomes deenergized, the clutch is released and the parts are restored as described in connection with the magnetic clutch associated with the tens selector bar 22, except that since the auxiliary armature yoke is pivoted on a vertical axis a spring is required for restoring it. This spring is not shown but is connected between the yoke and frame in any suitable maner so as to urge the actuating member 30 to the left. A stop screw 86 engaged by finger 29 determines the normal position of the parts.

Referring now to Fig. 4, this circuit drawing shows the tens solenoid 32, the tens operating magnet 11, and a relay 90 which may be a subscribers line relay, for example. The drawing also shows diagrammatically the set of contact springs associated with the solenoid 32 and indicates by a dotted line 9| a chain circuit including contact springs associated with other tens solenoids, which is provided in order to prevent more than one tens solenoid from energizing at a time. This is a detail which does not concern the invention and which, moreover, is fully disclosed in the Blackhall patent previously referred to.

The operation of the circuit will be obvious, especially in view of the detailed explanation of selector bar operation already made. Relay 90, upon energizing, closes a circuit for solenoid 32 at contact 92. Solenoid 32, upon energizing, breaks its initial energizing circuit at back contacts H and 68 and completes a locking circuit for itself at the front contact H. The contact springs are adjusted so that the locking circuit is completed before the initial energizingcircuit is broken. The energizing circuit for the operating magnet is completed at contacts 61.

Upon the deenergization of relay 90 the looking circuit of solenoid 32 is broken and the solenoid deenergizes, restoring the associated contacts to normal. The circuit of magnet I1 is broken at contact 61 and the magnet deenergizes also.

The circuit of the units solenoid l6 and the operating magnet I8 is not shown but may be generally similar to the circuit, Fig. 4.

The invention having been described, that which is believed to be new and for which the protection of letters patent is desired will be pointed out in the appended claims.

We claim:

1. In combination, an operating element, an electromagnetic clutch including two clutch elements one of which is movable to engage the other responsive to energization of the clutch, means for energizing said clutch to move the movable element thereof, a contact device actuated by movement of said movable clutch element, a magnet, a circuit for said magnet controlled by said contact device, and means con- 8 element through the medium of said energized clutch.

2. In combination, a fixed solenoid, two cores for said solenoid projecting from the opposite ends thereof and normally spaced apart inside the solenoid, an operating element attached to the first one of said cores, means for energizing said solenoid to bring said cores together, a spring opposing movement of said operating element, whereby only the second core is moved by energization of said solenoid, a circuit completed by the movement of the second core, and means including a magnet energized over said circuit for applying power to the second core to move both cores axially relative to said solenoid to actuate said operating element.

3. In combination, an actuating member, a traction member having a limited movement in one direction relative to said actuating member, a contact spring mounted on said actuating memher and tensioned to assist such movement, a stronger spring compressed between said members and operative to normally prevent such movement, a solenoid, means for energizing said solenoid, and a core for said solenoid attached to said traction member and operative to overcome the said stronger spring and move said traction member responsive to energization of said solenoid.

4. In combination, a solenoid, two cores for said solenoid, an operating element attached to one core, an actuating member associated with the other core, two springs acting on said cores, respectively, to maintain them separated inside said solenoid, the weaker of said springs acting on the second core and eiiective to maintain it out of operative relation to said actuating member, means for energizing said solenoid to move said second core into engagement with the first core and into operative relation to said actuating membenand means responsive to such movement on the second core to operate said actuating member.

5. In combination, an operating element, a solenoid, .a core for said solenoid attached to said element, a second corenormally separated from said first core, means for energizing said sole-- noid to move said second core into engagement with said first core, means including an operating magnet for moving said second core in a direction opposite to the direction of its first movement to move the first core and thereby operate said element, and means responsive 'to the first movement of said second core for closing a circuit for said magnet.

6. In combination, operating element, a magnetic member attached to said element, a second magneticmembermovablein two directions, means including a magnetizing winding for moving saidsecond member in one direction to efifect amagnetic coupling of said members, a circuit and means for closing it responsive to such movement of the'said second member, and means including a magnet energized over said circuit for moving second member in the other direction to operate said element.

7. In combination, a magnet, a pivoted armature operable by said magnet, a set of contacts mounted on said armature and movable with said armature responsiveto displacement thereof by the-energizaticn of said magnet, a solenoid having a movable core and an arm projecting therefrom which is elastically engaged by said armature and is maintained in normal position theretrolled by said, magnet to actuate said operating? by, an extension on said. arm adapted to actuate said contacts, said core and arm and extension thereof being so constructed and arranged with respect to said set of contacts that said contacts are actuated responsive to energization of said solenoid prior to displacement of said armature by the energization of said magnet.

8. The combination defined in claim 7, together with a movable member adapted to control the operation of contact making means, and means comprising said solenoid core for moving said last named member responsive to displacement of said armature by the energization of said magnet. 9. A magnetic clutch comprising a solenoid, an operating element, a core for said solenoid attached to said element, a second core in axial alignment with said first core but normally spaced away therefrom, means for energizing said solenoid to thereby move said second core inward to engage said first core, an operating magnet, circuit means actuated by said second core incident to the inward movement thereof responsive to the energization of said solenoid for energizing said magnet, and means operated by said magnet upon energization thereof for moving said second core outward to apply a tractive force to said first core to thereby move said operating element.

10. In combination, an operating element, an electromagnetic clutch comprising two relatively 10 movable clutch members, means for energizing said clutch to move one of said clutch members into engagement with the other clutch member, a magnet comprising a coil and an armature, means controlled by the clutch member which moves into engagement with the other clutch member for energizing the coil of said magnet to attract said armature, and means actuated by said armature for moving both clutch members to actuate said operating element.

ALEXANDER C. REID.

HANS P. BOSWAU.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 761,459 Eastwood May 31, 1904 899,598 Howard Sept. 29, 1908 1,017,198 Bender Feb. 13, 1912 1,034,397 Soldatencow July 30, 1912 1,124,599 Fessenden Jan. 12, 1915 1,690,300 Horton Nov. 6, 1928 1,699,514 Aldendorff Jan. 22, 1929 2,135,015 Richter Nov. 1, 1942 2,300,778 Cornwell Nov. 3, 1942 2,373,256 Miller Apr. 10, 1945 

